High Strength Low Weight Non-Woven Fabric And Containers Incorporating Same For Use In Preparing Beverages

ABSTRACT

A non-woven fabric is provided having a high strength and a low basis weight. The fabric comprises a plurality of multi-component fibers that are bonded together into a web having a basis weight of 20 gsm or less, an air porosity of at least 1600 L/M2/s and a bonding area percentage in the range of 15-50%, wherein the multi-component fibers include a sheath and at least one core that are each formed of the same substantially pure polymer material. The invention further provides a method of making the non-woven fabric as well as a filtered container or beverage capsule formed with the non-woven fabric.

FIELD

This specification relates to non-woven fabrics and in particular to fabrics having a high strength and a low basis weight for use in various applications including beverage filtration as well as containers formed with such fabrics.

BACKGROUND

The following background discussion is not an admission that anything discussed below is citable as prior art or common general knowledge. The documents listed below are incorporated herein in their entirety by this reference to them.

Non-woven fabrics are well known for a wide variety of applications ranging from clothing to beverage filtration and beyond.

It is desirable in some applications, such as filtration of coffee or tea, to utilize low basis weight non-woven fabrics in the range of 40 gsm or less. A problem with such low basis weight fabrics however is that they can be difficult to cut to a desired size on a commercial scale in a manner that does not impede the filtration functionality of the fabric. Specifically, a low basis weight nonwoven can be designed to be cuttable, but often the cuttable nonwoven is weak in strength which induces damages on the fabric (for example, a hole or tear) during manipulation of the filter into its final shape for application.

There is a need for a low basis weight non-woven fabric that has a sufficiently high strength that it may be cut, such as through a die cutting process, in a manner that does not impede the desired functionality of the fabric such as beverage filtration.

SUMMARY

In one aspect, the invention provides a non-woven fabric comprising a plurality of multi-component fibers that are formed together into a web having a basis weight of 20 gsm or less, an air porosity of at least 1600 L/M2/s and a plurality of bonds, said fabric having a bonding area percentage in the range of 15-50%, and wherein said multi-component fibers comprise a sheath and at least one core that are each formed of the same pure polymer material.

In another aspect, the invention provides a method for making a non-woven fabric comprising the steps of (i) spinning a set of multi-component fibers comprising a sheath and at least one core that are each formed of the same pure polymer material and (ii) positioning said set of multi-component fibers into a web; and (iii) bonding said set of multi-component fibers to produce a non-woven fabric having a basis weight of 20 gsm or less, an air porosity of at least 1600 L/M2/s and a bonding area percentage in the range of 15-50%.

In another aspect, the invention provides a filtered container adapted to contain desired ingredients for forming a beverage, said filtered container being formed from a non-woven fabric comprising a plurality of multi-component fibers that are bonded together into a web having a basis weight of 20 gsm or less, an air porosity of at least 1600 L/M2/s and a bonding area percentage in the range of 15-50%, wherein said multi-component fibers comprising a sheath and at least one core that are each formed of the same pure polymer material.

In another aspect, the invention provides a filtered container for use in forming a beverage, the filtered container comprising:

at least one piece of non-woven fabric that is formed into a container defining an interior space, said at least one piece of non-woven fabric having a plurality of multi-component fibers that are bonded together into a web having a basis weight of 20 gsm or less, an air porosity of at least 1600 L/M2/s and a bonding area percentage in the range of 15-50%, wherein said multi-component fibers comprising a sheath and at least one core that are each formed of the same pure polymer material; and ingredients disposed in said interior space to form the beverage.

In another aspect, the invention provides a beverage capsule for use in a beverage preparing machine, the beverage capsule comprising:

a body defining an interior space having an opening; a non-woven fabric disposed in said interior space, said non-woven fabric having a plurality of multi-component fibers that are bonded together into a web having a basis weight of 20 gsm or less, an air porosity of at least 1600 L/M2/s and a bonding area percentage in the range of 15-50%, wherein said multi-component fibers comprising a sheath and at least one core that are each formed of the same pure polymer material; ingredients disposed in said interior space to form the beverage; and a cover disposed over said opening.

Other aspects and features of the teachings disclosed herein will become apparent to those ordinarily skilled in the art, upon review of the following description of the specific examples of the specification.

DRAWINGS

The drawings included herewith are for illustrating various examples of articles, methods, and apparatuses of the present specification and are not intended to limit the scope of what is taught in any way. For simplicity and clarity of illustration, where considered appropriate, reference numerals may be repeated among the drawings to indicate corresponding or analogous elements.

FIG. 1 is a schematic view of a web of non-woven fabric in accordance with one aspect of the present invention;

FIG. 2 is a schematic cross-sectional view of a multi-component fiber used in the formation of an embodiment of the fabric of the present invention;

FIGS. 3(a) and 3(b) are schematic enlarged views of different shapes of bonds formed on embodiments of the fabric of the present invention;

FIGS. 4(a) and 4(b) are schematic views of different shapes of bond tips disposed on a calendar roll for forming bonds on embodiments of the fabric of the present invention;

FIG. 5 (a) is a plan view of an embodiment of a filtered container formed with an embodiment of the fabric of the present invention;

FIG. 5(b) is a sectional view of the filtered container of FIG. 5(a) as viewed along lines b-b;

FIG. 5(c) is a perspective view of another embodiment of a filtered container formed with an embodiment of the fabric of the present invention; and

FIG. 6 is a side sectional view of a beverage capsule having a filter formed with an embodiment of the fabric of the present invention.

DESCRIPTION OF VARIOUS EMBODIMENTS

Various apparatuses or methods will be described below to provide examples of the claimed invention. The claimed invention is not limited to apparatuses or methods having all of the features of any one apparatus or method described below or to features common to multiple or all of the apparatuses described below. The claimed invention may reside in a combination or sub-combination of the apparatus elements or method steps described below. It is possible that an apparatus or method described below is not an example of the claimed invention. The applicant(s), inventor(s) and/or owner(s) reserve all rights in any invention disclosed in an apparatus or method described below that is not claimed in this document and do not abandon, disclaim or dedicate to the public any such invention by its disclosure in this document.

A non-woven fabric or web (referred to as “fabric” or “non-woven fabric” hereafter) in accordance with an embodiment of the present invention is shown schematically at 10 in FIG. 1 . Fabric 10 preferably has a basis weight of 20 gsm or less, more preferably 15 gsm or less and even more preferably 10 gsm or less. Fabric 10 is preferably adapted to meet local food safety requirements such as the requirements of FDA 21 CFR 176.170 condition B, Components of Paper and Paperboard in Contact with Aqueous and Fatty Foods

Fabric 10 is formed from a plurality of multi-component fibers 12 that are interlaid and formed into fabric 10 through a desired fabric forming process. Preferably, fabric 10 is formed with a spunbond process.

Fabric 10 is subsequently passed through one or more calendar rolls to form bonds 14 (in one embodiment fabric may be passed between a calendar roll and an anvil roll). Examples of bonds are shown in FIGS. 3(a) (round bond) and 3(b) (oval bond). Bonds 14 preferably each have an edge profile 16 that is curvilinear and each bond 14 is preferably either circular or oval with a surface area ranging from 0.2 to 0.5 mm2.

Bonds 14 are preferably formed using a heated calendar (not shown) having a plurality of bonding tips 15 extending from the surface of the calendar as shown in FIG. 4(a) (round tip) and FIG. 4(b) (oval tip). Bonding tips 15 preferably have rounded/smooth edges instead of sharp 90° edges. Fabric 10 preferably has a bonding area percentage optimization in the range of 15-50% of the total fabric area and more preferably in the range of 20-35%.

Referring to FIG. 2 , multi-component fibers 12 include a sheath 18 and a core 20. Core 20 may comprise a single core 20 or may comprise multiple core elements 20(i) . . . 20(n) disposed for example in an islands-in-the-sea configuration or a segmented pie configuration. Sheath 18 and core 20 are each formed from a pure polymer material selected from the same polymer family such as PP, PET or PLA.

Fibers 12 preferably have a thickness of at least two denier (D) preferably 2-4 D and more preferably 2-3D. The percentage of core 20 relative to the overall fiber ranges from 40-80% by weight with a preferred range of 50-70%.

Fibers 12 are preferably formed from high strength pure resins such as PP, PET or PLA. For example, fibers 12 formed of PP preferably have a notched Izod impact strength of at least 15 J/m at 23 degrees C. (using ASTM D256 test method).

Fabric 10 preferably has a tear strength in the range of 5-10 N, and more preferably in the range of 8-10 N, in both the machine direction MD and the cross direction CD.

Fabric 10 is adapted to be cut, such as by a die-cutting process with a serrated knife, to a desired size. For example, fabric 10 may be cut into a disc shape with a diameter ranging from 30 mm to 150 mm (cutting speed can vary from 30 to 100 cycles per minute), for subsequent use as a filter in a beverage capsule (as shown and described below). Alternatively, fabric 10 may be cut into shapes to form filtered containers, such as tea bags or coffee pods, as described below. The high strength properties of fabric 10 allow fabric 10 to be cut without the formation of tears or unintended perforations or holes in fabric.

Fabric 10 preferably has an air porosity of at least 1600 L/m2/s (based on ISO9037:1995) while still providing the desired performance characteristics such as beverage filtration.

Fabric 10 is preferably intended for use as a beverage filter for filtering insoluble ingredients such as tea or roast ground coffee.

In the embodiments shown in FIGS. 5(a) to 5(c), at least one piece of fabric 10 is cut and (if necessary) folded onto itself to form a filtered container 30 (such as a flat or pyramid shaped pod, bag or sachet) with edges 32 sealed together to define a chamber 34 that is adapted to hold ingredients 36 such as coffee or tea. Container 30 is adapted to allow a beverage to be formed from such ingredients when mixed with a fluid such as water.

In another embodiment, as shown in FIG. 6 , fabric 10 is cut and sealed within a beverage capsule 40 to define an ingredients chamber 42 for holding desired ingredients 44 such as tea or roast and ground coffee. Capsule 40 further includes a body 46, defining an opening 48, and a cover 50 for sealing the opening 48. Body 46 and cover 50 are each adapted to be pierced in a beverage machine (not shown) to allow a fluid, such as water, to be injected into the capsule 40 to mix with the ingredients 44 and a resulting beverage to be dispensed from the capsule 40 into a user's cup (not shown). Body 46 includes a base 52 and a sidewall 54 with fabric 10 preferably being sealed to sidewall 54 within an interior space 56 defined in capsule 40.

While the above description provides examples of one or more processes or apparatuses, it will be appreciated that other processes or apparatuses may be within the scope of the accompanying claims. 

I/We claim:
 1. A non-woven fabric comprising a plurality of multi-component fibers that are formed together into a web having a basis weight of 20 gsm or less, an air porosity of at least 1600 L/M2/s and a plurality of bonds, said fabric having a bonding area percentage in the range of 15-50%, and wherein said multi-component fibers comprise a sheath and at least one core that are each formed of the same pure polymer material.
 2. The fabric of claim 1 wherein said fabric is a spunbond fabric.
 3. The fabric of claim 1 wherein said multi-component fibers have a diameter of at least two denier (D).
 4. The fabric of claim 1 wherein said multi-component fibers are bonded together into a web with a curvilinear bonding pattern edge profile.
 5. The fabric of claim 1 wherein said multi-component fibers are formed from resins having a notched Izod impact strength of at least 15 J/m at 23 degrees C.
 6. The fabric of claim 1 wherein said pure polymer material is selected from PP, PET or PLA.
 7. The fabric of claim 1 wherein said fabric has a material tear strength in the range of 5-10 N in both the Machine Direction (MD) and the Cross Direction (CD).
 8. A filtered container for use in forming a beverage, the filtered container comprising: a) at least one piece of non-woven fabric that is formed into a container defining an interior space, said at least one piece of non-woven fabric having a plurality of multi-component fibers that are bonded together into a web having a basis weight of 20 gsm or less, an air porosity of at least 1600 L/M2/s and a bonding area percentage in the range of 15-50%, wherein said multi-component fibers comprising a sheath and at least one core that are each formed of the same pure polymer material; and b) ingredients disposed in said interior space to form the beverage.
 9. The filtered container of claim 8 wherein said fabric is a spunbond fabric.
 10. The filtered container of claim 8 wherein said multi-component fibers have a diameter of at least two denier (D).
 11. The filtered container of claim 8 wherein said multi-component fibers are bonded together into a web with a curvilinear bonding pattern edge profile.
 12. The filtered container of claim 8 wherein said multi-component fibers are formed from resins having a notched Izod impact strength of at least 15 J/m at 23 degrees C.
 13. The filtered container of claim 8 wherein said pure polymer material is selected from PP, PET or PLA.
 14. A beverage capsule for use in a beverage preparing machine, the beverage capsule comprising: a) a body defining an interior space having an opening; b) a non-woven fabric disposed in said interior space, said non-woven fabric having a plurality of multi-component fibers that are bonded together into a web having a basis weight of 20 gsm or less, an air porosity of at least 1600 L/M2/s and a bonding area percentage in the range of 15-50%, wherein said multi-component fibers comprising a sheath and at least one core that are each formed of the same pure polymer material; c) ingredients disposed in said interior space to form the beverage; and d) a cover disposed over said opening.
 15. The beverage capsule of claim 14 wherein said fabric is a spunbond fabric.
 16. The beverage capsule of claim 14 wherein said multi-component fibers have a diameter of at least two denier (D).
 17. The beverage capsule of claim 14 wherein said multi-component fibers are bonded together into a web with a curvilinear bonding pattern edge profile.
 18. The beverage capsule of claim 14 wherein said multi-component fibers are formed from resins having a notched Izod impact strength of at least 15 J/m at 23 degrees C.
 19. The beverage capsule of claim 14 wherein said pure polymer material is selected from PP, PET or PLA.
 20. The beverage capsule of claim 14 wherein said fabric has a material tear strength in the range of 5-10 N in both the Machine Direction (MD) and the Cross Direction (CD). 